CN101220227A - Pigment dispersion, ink composition, ink set, and recording device - Google Patents

Abstract

The present invention provides a pigment dispersion liquid, an ink composition, an ink set, and a recording device with a high metallic specular gloss, focusing on aluminum as a relatively inexpensive metal material. The pigment dispersion liquid is a pigment dispersion liquid containing a metal pigment, and the metal pigment is a tabular particle. When the long axis of the flat particle on a plane is X, the short axis is Y, and the thickness is Z, from the The 50% average particle diameter R50 of the equivalent circle diameter calculated from the area of the XY plane of the flat particles is 0.5-3 μm, and satisfies the condition of R50/Z>5.

Description

Pigment dispersion, ink composition, ink set, and recording device

technical field

The present invention relates to a pigment dispersion liquid, an ink composition, an ink combination and a recording device, in particular to a pigment dispersion liquid, an ink composition, an ink combination and a recording device capable of forming images with metallic luster.

Background technique

Conventionally, in order to form a coating film with a metallic luster on printed matter, printing inks using gold powder or silver powder made of brass, aluminum particles, etc. as pigments, foil printing using metal foil, and thermal transfer printing using metal foil printing method etc.

However, although the average particle diameter of the metal powder used is as large as 10 μm to 30 μm, a coating film using printing ink using gold powder or silver powder can obtain a matte metallic luster, but it is difficult to obtain a specular gloss. In addition, in the press foil or thermal transfer using metal foil, an adhesive is applied on the printing medium, a smooth metal foil is pressed on it, the recording medium and the metal foil are adhered, and the metal foil is bonded to the metal foil by heating. A method of thermally welding a recording medium or the like. Therefore, although good gloss can be obtained, there are many manufacturing steps, and pressure and heat are applied during the manufacturing steps. Therefore, there are restrictions on recording media that are relatively strong against heat or deformation.

In recent years, many application examples of inkjet printing have been seen, and metal printing is included as one of the application examples. For example, Japanese Unexamined Patent Publication No. 2002-179960 discloses a technique of forming a metal coating on the surface of spherical plastic particles and printing an ink composition containing the pigment by inkjet printing (Patent Document 1). However, in order to obtain a high metallic luster, the sphere must be deformed and flattened to smooth the surface. In this technique, pressing with a roller and heat treatment must be performed at the same time. Therefore, from this point of view, it cannot be avoided that the device or the manufacturing process becomes complicated, and the recording medium is also limited.

In addition, JP-A-2003-292836 also discloses a technology using an ink composition in which precious metal colloids such as gold and silver are dispersed (Patent Documents 2 and 3). However, if the dispersion stability of the noble metal colloid is prioritized and the particle size is reduced to a few nm to several tens of nm, coloring due to plasmon absorption occurs, and the metallic luster of the ink composition cannot be obtained. In this case, after the coating film is dried, the colloidal particles are fused by heat treatment at a temperature of 150° C. or higher to obtain a metallic luster. Furthermore, even though metallic luster can be obtained with these techniques, it is difficult to obtain high metallic specular gloss with specular gloss levels exceeding 200, 200, and 200 at 20°, 60°, and 85°, respectively, on a uniform surface without unevenness. In addition, when the particle size is increased by giving priority to metallic luster, problems such as lowering of dispersion stability, aggregation or sedimentation cannot be avoided, and the storage life of the ink composition is significantly reduced. In addition, it goes without saying that the use of precious metals as materials greatly increases the cost of the ink composition, so it is only used for applications with high added value, which is disadvantageous in terms of cost.

Patent Document 1: JP-A-2002-179960

Patent Document 2: JP-A-2003-292836

Patent Document 3: JP-A-2003-306625

Contents of the invention

The present invention focuses on aluminum as a relatively inexpensive metal material, and aims to provide a pigment dispersion liquid, an ink composition, and a recording device having high metallic specular gloss.

Another object of the present invention is to provide an ink set capable of forming coating films having different metallic luster on printed matter by constituting an ink set containing ink compositions having different concentrations of metallic pigments.

In order to solve the above-mentioned problems, the inventors of the present invention conducted intensive studies, and as a result found that a metal pigment dispersion liquid, an ink composition, an ink set, and a recording device using a specific metal pigment can obtain a mirror surface with such a high level that it was impossible before. Glossy print. The present invention has been made based on such findings, and provides the following inventions.

[1] A pigment dispersion liquid, which is a pigment dispersion liquid containing a metal pigment, wherein,

The metal pigment is a flat particle, and when the long axis of the flat particle on a plane is X, the short diameter is Y, and the thickness is Z, the equivalent circle obtained from the area of the X-Y plane of the flat particle is The 50% average particle diameter R50 of the diameter is 0.5-3 μm, and the condition of R50/Z>5 is satisfied.

[2] The pigment dispersion according to [1], wherein,

The maximum particle diameter Rmax of the equivalent circle diameter obtained from the area of the X-Y plane of the flat particles is 10 μm or less.

[3] The pigment dispersion according to [1], wherein

The metal pigment is aluminum or aluminum alloy.

[4] The pigment dispersion according to [1], wherein,

The metal pigment is produced by crushing a metal vapor-deposited film.

[5] The pigment dispersion according to [1], wherein,

The particle size distribution CV value of the metallic pigment obtained by the following formula is 60 or less.

[Formula 1]

CV value = standard deviation of particle size distribution / average value of particle size × 100

[6] An ink composition, wherein,

Contains the pigment dispersion liquid described in [1], an organic solvent, and a resin.

[7] The ink composition according to [6], wherein

The concentration of the metal pigment in the ink composition is 0.1-3.0% by weight.

[8] The ink composition according to [6], wherein

The organic solvent contains one or more kinds of alkylene glycol ethers that are liquid at normal temperature and normal pressure.

[9] The ink composition according to [6], wherein

The organic solvent is a mixture of alkylene glycol diether, alkylene glycol monoether and lactone.

[10] The ink composition according to [6], wherein

The resin is at least one selected from the group consisting of polyvinyl butyral, cellulose acetate butyrate, and polyacrylic acid polyol.

[11] The ink composition according to [6], wherein

The ink composition contains at least one or more acetylene glycol-based and/or silicone-based surfactants.

[12] The ink composition according to [6], wherein

When being applied to the inkjet recording device that the nozzle diameter L μ m of the inkjet head and the mesh W μ m of the mesh filter arranged in the ink flow path meet the condition of L≥5W, the area of the X-Y plane of the flat particle is calculated The number of plate-shaped particles whose average particle diameter R μm of equivalent circle diameter satisfies the condition of R>(L/5) is 5% or less of the total number of the above-mentioned plate-shaped particles.

[13] A combination ink, wherein,

There are plural kinds of ink compositions according to [6], each of which has a different metal pigment concentration.

[14] The ink set according to [13], wherein,

In the ink composition, the concentration of the metal pigment in at least one ink composition is 0.1% by weight or more and less than 1.5% by weight, and the concentration of the metal pigment in the other at least one ink composition is 1.5% by weight Above and below 3.0% by weight.

[15] A recording device in which,

The ink set described in [13] is provided.

According to the present invention, by using a metallic pigment having a particle diameter controlled to a specific shape, an image having such a high metallic gloss (so-called metallic gloss) that has not been possible before can be formed on a recording medium.

Description of drawings

FIG. 1 is an exploded perspective view illustrating the structure of a recording head.

FIG. 2 is a cross-sectional view illustrating the structure of an ink introduction needle.

In the figure, 3-recording head, 15-base platform, 16-head case, 17-flow channel unit, 18-net filter, 19-ink liquid introduction needle, 20-circuit board, 21-piece shape member, 22-vibrator unit, 23-elastic plate, 24-flow path forming substrate, 25-nozzle plate, 26-nozzle opening, 27-nozzle cover, 37-ink communication port, 41-ink introduction path, 42 -Ink inlet hole.

Detailed ways

[Pigment dispersion]

The pigment dispersion liquid in this embodiment is a pigment dispersion liquid containing a metallic pigment (hereinafter referred to as "metallic pigment"). The metallic pigment is a tabular particle made by crushing a metal vapor deposition film. In the case where the major axis is X, the minor axis is Y, and the thickness is Z, the 50% average particle diameter R50 of the equivalent circle diameter obtained from the area of the X-Y plane of the flat-shaped particle is 0.5 to 3 μm, and R50 is satisfied. The condition of /Z>5.

The "plate-shaped particle" means a particle having a substantially flat surface (X-Y plane) and having a substantially uniform thickness (Z). Since the tabular particles are produced by crushing the vapor-deposited metal film, metal particles with a substantially flat surface and substantially uniform thickness can be obtained. Therefore, X can be defined as the long axis of the flat particle on a plane, Y can be defined as the short axis, and Z can be defined as the thickness.

"Equivalent circle diameter" means the diameter of a circle when the substantially flat surface (X-Y plane) of the metallic pigment tabular particle is assumed to be a circle having the same projected area as the projected area of the metallic pigment particle. For example, when the substantially flat surface (X-Y plane) of the tabular particle of the metallic pigment is a polygon, the diameter of the circle obtained by converting the polygonal projection surface into a circle is called the equivalent circle diameter of the tabular particle of the metallic pigment. .

From the viewpoint of metallic luster and printing stability, the 50% average particle diameter R50 of the equivalent circle diameter calculated from the area of the X-Y plane of the flat particles is preferably 0.5 to 3 μm, more preferably 0.75 to 2 μm. When the 50% average particle size R50 is less than 0.5 μm, the gloss is insufficient. On the other hand, in the case where the 50% average particle diameter R50 exceeds 3 μm, printing stability decreases.

In addition, the relationship between the 50% average particle diameter R50 of the equivalent circle diameter and the thickness Z is R50/Z>5 from the viewpoint of ensuring high metallic luster. When R50/Z is 5 or less, there exists a problem that metallic luster is insufficient.

From the viewpoint of preventing clogging of the ink composition in the inkjet recording device, the maximum particle diameter Rmax of the equivalent circle diameter obtained from the area of the X-Y plane of the tabular particles is preferably 10 μm or less. By setting Rmax to 10 μm or less, it is possible to prevent clogging of the nozzles of the inkjet recording device, the mesh filter provided in the ink flow path, and the like.

From the viewpoint of cost and ensuring metallic luster, the metallic pigment is preferably aluminum or an aluminum alloy. When an aluminum alloy is used, other metal elements or nonmetal elements added to aluminum are not particularly limited as long as they have functions such as metallic luster, and examples include silver, gold, platinum, nickel, and chromium. , tin, zinc, indium, titanium, copper, etc., preferably use at least one of their monomers, their alloys, and their mixtures.

The method for producing the metal pigment is, for example, combining the metal or alloy layer and the peeling resin layer of a complex pigment original body composed of a structure in which a peeling resin layer and a metal or alloy layer are sequentially laminated on the surface of a sheet-like substrate. Using the interface as a boundary, the plate-shaped particles are obtained by exfoliating, pulverizing, and miniaturizing from the sheet-like substrate. Next, when the long axis on the plane of the obtained flat particle is X, the short diameter is Y, and the thickness is Z, the equivalent circle diameter obtained from the area of the X-Y plane of the flat particle is The 50% average particle size R50 is 0.5-3 μm, and the condition of R50/Z>5 is satisfied.

The major axis X, minor axis Y, and circle-equivalent diameter of the metal pigment (plate-like particle) on a plane can be measured using a particle image analyzer. As the particle image analyzer, flow type particle image analyzers FPIA-2100, FPIA-3000, and FPIA-3000S manufactured by Sysmex Corporation, for example, can be used.

The particle size distribution (CV value) of the metallic pigment (tabular particles) can be obtained from the following formula.

[Formula 1]

CV value = standard deviation of particle size distribution / average value of particle size × 100

Here, the obtained CV value is preferably 60 or less, more preferably 50 or less, and still more preferably 40 or less. By selecting a metallic pigment with a CV value of 60 or less, excellent printing stability can be obtained.

The metal or alloy layer is preferably formed by vacuum evaporation, ion plating or sputtering.

The metal or alloy layer is formed to have a thickness of not less than 20 nm and not more than 100 nm. In this way, a pigment having an average thickness of not less than 20 nm and not more than 100 nm can be obtained. By making it 20 nm or more, reflectivity and brightness are excellent, and the performance as a metal pigment becomes high, and by making it 100 nm or less, the increase of apparent specific gravity can be suppressed, and the dispersion stability of a metal pigment can be ensured.

The peeling resin layer of the composite pigment precursor is an undercoat layer of the metal or alloy layer, and is a peelable layer for improving peelability from the surface of the sheet-like substrate. As the resin used for the peeling resin layer, for example, polyvinyl alcohol, polyvinyl butyral, polyethylene glycol, polyacrylic acid, polyacrylamide, cellulose derivatives, acrylic polymers, or modified nylon resins are preferable.

A solution of one or more mixtures of the above-mentioned ones is applied to a recording medium, and drying or the like is performed to form a layer. Additives such as viscosity modifiers may be added after coating.

The coating of the peeling resin layer can be formed by commonly used gravure coating, roll coating, blade coating, extrusion coating, dip coating, spin coating, or the like. After coating and drying, the surface is smoothed by calendering if necessary.

The thickness of the peeling resin layer is not particularly limited, but is preferably 0.5 to 50 μm, more preferably 1 to 10 μm. When the thickness is less than 0.5 μm, the amount of the dispersion resin is insufficient, and when it exceeds 50 μm, the pigment layer is easily peeled off at the interface when roll-forming is performed.

The sheet-like substrate is not particularly limited, and polyester films such as polytetrafluoroethylene, polyethylene, polypropylene, and polyethylene terephthalate; polyamide films such as 66 nylon and 6 nylon , Polycarbonate film, triacetate film, polyimide film and other release films. A preferable sheet-like substrate is polyethylene terephthalate or a copolymer thereof.

The thickness of these sheet-like substrates is not particularly limited, but it is preferably 10 to 150 μm. If it is more than 10 μm, there will be no problem with handling in the process. There is no problem.

In addition, as shown in Japanese Unexamined Patent Publication No. 2005-68250, the metal or alloy layers may be sandwiched by protective layers. Examples of the protective layer include a silicon oxide layer and a protective resin layer.

The silicon oxide layer is not particularly limited as long as it contains silicon oxide, but is preferably formed of a silane oxide such as tetraalkoxysilane or a polymer thereof by a sol-gel method.

A coating film of a silicon oxide layer is formed by applying and heating an alcohol solution in which the above-mentioned silane oxide or its polymer is dissolved.

The protective resin layer is not particularly limited as long as it is a resin that is insoluble in the dispersion medium, examples of which include vinyl alcohol, polyethylene glycol, polyacrylic acid, polyacrylamide, cellulose derivatives, etc., preferably Formed from polyvinyl alcohol or cellulose derivatives.

A layer obtained by applying, drying, or the like to an aqueous solution of one or a mixture of two or more of the above-mentioned resins is formed. The coating liquid may contain additives such as a viscosity modifier.

Coating of the above-mentioned silicon oxide and resin can be performed by the same method as that of the above-mentioned coating of the resin layer for release.

The thickness of the protective layer is not particularly limited, but is preferably in the range of 50 to 150 nm. When the thickness is less than 50 nm, the mechanical strength is insufficient, and when the thickness exceeds 150 nm, the strength becomes too high, so pulverization and dispersion become difficult, and there is a possibility of peeling at the interface with the metal or alloy layer.

In addition, as exemplified in Japanese Unexamined Patent Application Publication No. 2005-68251, a coloring material layer may be provided between the "protective layer" and the "metal or alloy layer".

The coloring material layer is a layer introduced to obtain any colored composite pigment, as long as it contains a coloring material that can impart any color tone and hue in addition to the metallic luster and brightness of the metallic pigment used in the present invention. Yes, there is no particular limitation. As the coloring material used in the coloring material layer, any of dyes and pigments may be used. In addition, well-known dyes and pigments can be used suitably as a dye and a pigment.

In this case, the "pigment" used in the color material layer refers to natural pigments, synthetic organic pigments, synthetic inorganic pigments, etc. defined in the field of general pigment chemistry, and processed into "composite pigments" of the present invention, etc. Pigments with a layered structure are different.

The method for forming the color material layer is not particularly limited, but it is preferably formed by coating.

In addition, when the color material used in the color material layer is a pigment, it is preferable to further contain a color material dispersing resin, and as the color material dispersing resin, it is preferable to disperse the pigment, the color material dispersing resin, and other additives if necessary. Alternatively, it can be dissolved in a solvent to make a solution, and a uniform liquid film can be formed by spin coating, and then dried to form a resin film.

Among them, in the production of the composite pigment original body, it is preferable to perform the above-mentioned color material layer together with the formation of the protective layer by coating in terms of operational efficiency.

The composite pigment original body may have a layer structure in which a plurality of the peeling resin layer, the metal or alloy layer, and the protective layer are sequentially laminated. At this time, the overall thickness of the laminated structure composed of a plurality of metal or alloy layers is the metal or alloy-resin layer for peeling-metal or alloy layer, or the resin layer for peeling, excluding the sheet-like base material and the resin layer for peeling directly above it. The thickness of the resin layer-metal or alloy layer is preferably 5000 nm or less. If it is 5000 nm or less, even when the composite pigment original body is wound into a roll, cracks and peeling are less likely to occur, and the preservability is excellent. Moreover, when it is made into a pigment, it is preferable because it is excellent in brightness.

In addition, a structure in which a peeling resin layer and a metal or alloy layer are sequentially laminated on both surfaces of the sheet-like base material can also be mentioned, but it is not limited to these.

The peeling treatment method from the sheet-like base material is not particularly limited, but a method of immersing the composite pigment body in a liquid, or performing ultrasonic treatment while immersing in a liquid, performing peeling treatment, and A method of pulverizing the exfoliated composite pigment.

In the pigment obtained as described above, the peeling resin layer functions as a protective colloid, and a stable dispersion liquid can be obtained only by a dispersion treatment in a solvent. In addition, in the ink composition using the pigment, the resin derived from the peeling resin layer also has the function of imparting adhesiveness to recording media such as paper.

[Ink composition]

The ink composition used in the inkjet recording method of this embodiment contains the above-mentioned metallic pigment, an organic solvent, and a resin.

In the case that only one of the combined inks is a metal pigment, the concentration of the metal pigment in the ink composition is preferably 0.1 to 3.0% by weight, more preferably 0.25 to 2.5% by weight, and even more preferably 0.5 to 2% by weight. weight%.

In the case of multiple metal ink compositions in the combined ink, the concentration of the metal pigment in the ink composition is preferably: the metal pigment of at least one ink composition in the ink composition The concentration of the metal pigment in at least one ink composition is more than 0.1% by weight and less than 1.5% by weight, and the concentration of the metal pigment of the other at least one ink composition is more than 1.5% by weight and less than 3.0% by weight.

When the concentration of the metal pigment in the ink composition is 0.1% by weight or more and less than 1.5% by weight, the amount of ink that cannot sufficiently cover the printing surface can be ejected, and a half-mirror shape can be felt. The glossy surface is the glossy feeling, which can be printed as a transparent and visible background. By spraying enough ink to cover the printing surface, a high-gloss metallic glossy surface can be formed. Therefore, it is suitable, for example, when forming a transflective mirror image on a transparent recording medium or when expressing a high-gloss metallic glossy surface. In addition, when the concentration of the metal pigment in the ink composition is 1.5% by weight or more and 3.0% by weight or less, the metal pigment is randomly arranged on the printing surface, so high gloss cannot be obtained, and a matte tone metallic color can be formed. glossy surface. Therefore, it is suitable, for example, when forming a shield layer on a transparent recording medium.

As the organic solvent, a polar organic solvent is preferably used, for example, alcohols (such as methanol, ethanol, propanol, butanol, isopropanol, or fluorinated alcohols, etc.), ketones (such as acetone, methyl ethyl alcohol, etc.) can be used. methyl ketone, or cyclohexanone, etc.), carboxylic acid esters (such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate or ethyl propionate, etc.) or ethers (such as di Ethyl ether, dipropyl ether, tetrahydrofuran or dioxane, etc.), etc.

The organic solvent particularly preferably contains one or more alkylene glycol ethers that are liquid at normal temperature and normal pressure.

Alkylene glycol ethers are aliphatic with methyl, n-propyl, isopropyl, n-butyl, isobutyl, hexyl, and 2-ethylhexyl, allyl with double bond and phenyl Ethylene glycol-based ethers and propylene glycol-based ethers are colorless, have little taste, and have ether groups and hydroxyl groups in the molecule, so they have the characteristics of both alcohols and ethers. They are liquid at room temperature substance. In addition, there are monoether types in which only one hydroxyl group is substituted and diether types in which both hydroxyl groups are substituted, and multiple types of these can be used in combination.

The organic solvent is particularly preferably a mixture of alkylene glycol diethers, alkylene glycol monoethers and lactones.

Examples of alkylene glycol monoethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monoethyl ether, and ethylene glycol monoethyl ether. Phenyl ether, Diethylene glycol monomethyl ether, Diethylene glycol monoethyl ether, Diethylene glycol monobutyl ether, Diethylene glycol dimethyl ether, Diethylene glycol diethyl ether, Triethylene glycol monomethyl ether, Triethylene glycol monoethyl ether, three Glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, etc.

Examples of the alkylene glycol diether include ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, diglyme, diethylene glycol diethyl ether, and diethylene glycol dibutyl ether. ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol dibutyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether , Dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, etc.

Moreover, examples of lactones include γ-butyrolactone, δ-valerolactone, and ε-caprolactone.

By adopting such a preferable structure, the object of the present invention can be further achieved.

Examples of the resin used in the ink composition include acrylic resins, styrene-acrylic resins, rosin-modified resins, terpene-based resins, polyester resins, polyamide resins, epoxy resins, and vinyl chloride resins. , vinyl chloride-vinyl acetate copolymer, cellulosic resins (such as cellulose acetate butyrate, hydroxypropyl cellulose), polyvinyl butyral, polyacrylic polyol, polyvinyl alcohol, polyurethane, etc.

In addition, non-aqueous emulsion polymer particles (NAD=Non Aqueous Dispersion) can also be used as resin. This is a dispersion liquid in which fine particles such as urethane resin, acrylic resin, and acrylic polyol resin are dispersed stably in an organic solvent.

For example, polyurethane resins include Sampuren IB-501 and Sampuren IB-F370 manufactured by Sanyo Chemical Industry Co., Ltd., and examples of acrylic polyol resins include N-2043- 60MEX, N-2043-AF-1.

In order to further improve the fixability of the pigment to the recording medium, it is preferable to add the resin emulsion to the ink composition in an amount of not less than 0.1% by weight and not more than 10% by weight. If the amount added is excessive, printing stability cannot be obtained, and if it is too small, the fixation becomes insufficient.

The ink composition preferably contains at least one of glycerin, polyalkylene glycol, or sugar. It is preferable to add 0.1 weight% or more and 10 weight% or less to an ink composition with respect to the total amount of these one or more types of glycerin, polyalkylene glycol, or sugar.

According to such a preferable structure, drying of the ink can be suppressed to prevent clogging, and at the same time, ejection of the ink can be stabilized to improve the image quality of the recorded matter.

The polyalkylene glycol is a linear polymer compound having a repeating structure of an ether bond in the main chain, and is produced, for example, by ring-opening polymerization of a cyclic ether or the like.

Specific examples of polyalkylene glycols include polymers such as polyethylene glycol and polypropylene glycol, ethylene oxide-propylene oxide copolymers and derivatives thereof, and the like. As the copolymer, any of random copolymers, block copolymers, graft copolymers, alternating copolymers, and the like can also be used.

Preferable specific examples of polyalkylene glycols include those represented by the following formulae.

OH-(CnH ₂ nO)mH

(In the above formula, n represents an integer of 1 to 5, and m represents an integer of 1 to 100)

However, in the above formula, (CnH ₂ nO)m may be a single constant or a combination of two or more numbers within the range of the integer value n. For example, when n is 3, it is (C ₃ H ₆ O)m, and when n is a combination of 1 and 4, it is (CH ₂ OC ₄ H ₈ O)m. In addition, the integer value m may be a single constant or a combination of two or more numbers within this range. For example, in the above example, when m is a combination of 20 and 40, it is (CH ₂ O) ₂₀ -(C ₂ H ₄ O) ₄₀ , and when m is a combination of 10 and 30, it is (CH ₂ O) ₁₀ -(C ₄ H ₈ O) ₃₀ . Furthermore, the integer values n and m may be combined arbitrarily within the above range.

Examples of sugars include monosaccharides such as pentose, hexose, heptose, and octose, polysaccharides such as disaccharides, trisaccharides, and tetrasaccharides, and sugar alcohols and deoxyacids that are derivatives thereof. Reduced derivatives such as aldonic acid and uronic acid, acidified derivatives such as aldonic acid and uronic acid, dehydrated derivatives such as anti-alcohol, amino acids, thiosugars, etc. Polysaccharides refer to sugars in a broad sense, including alginic acid, dextrin, and cellulose, which are widely found in nature.

The ink composition preferably contains at least one or more acetylene glycol-based surfactants and/or silicone-based surfactants. The surfactant is preferably added in an amount of not less than 0.01% by weight and not more than 10% by weight relative to the content of the pigment in the ink composition.

With such a preferable structure, the wettability of the ink composition to the recording medium can be improved, and fast fixability can be obtained.

As the acetylene diol-based surfactant, preferably, Sahui Nuolu (Surfinol) 465 (trademark) and Sahui Nuolu (Surfinol) 104 (trademark) (the above are trade names, Air Products and Chemicals. Inc.), Oruf (Orfine) STG (trademark) and Orfine (Orfine) E1010 (the above are trade names, manufactured by Nissin Chemical Co., Ltd.), etc.

As the silicone-based surfactant, polyester-modified silicone or polyether-modified silicone is preferably used. Specific examples include BYK-347, BYK-348, BYK-UV3500, BYK-UV3570, BYK-UV3510, BYK-UV3530 (BYK-Chemie Japan Co., Ltd.).

The ink composition can be prepared by a known conventional method. For example, initially, after mixing the metal pigment, the dispersant, and the liquid medium, prepare a pigment dispersion with a ball mill, bead mill, ultrasonic or jet mill, etc., and adjust it to have the required ink properties. . Next, the binder resin, the liquid medium, and other additives (such as dispersing aids or viscosity modifiers) are added under stirring to obtain a pigment ink composition.

In addition, it is also possible to temporarily ultrasonically treat the composite pigment original body in a liquid medium to become a composite pigment dispersion, and then mix it with the necessary liquid medium for ink. In addition, it is also possible to directly ultrasonically process the composite pigment in the liquid medium for ink. The original pigment is converted into an ink composition directly.

The physical properties of the ink composition are not particularly limited, for example, the surface tension thereof is preferably 20-50 mN/m. If the surface tension is less than 20mN/m, the ink composition wets and expands or oozes out to the surface of the printer head for inkjet recording, and the ejection of ink droplets becomes difficult. The surface of the medium does not spread wet, and good printing cannot be performed.

[Combined Ink]

The ink set used in the inkjet recording method of the present embodiment is an ink set comprising a plurality of ink compositions described above, and each ink composition has a different metal pigment concentration.

In the ink composition, the concentration of the metal pigment in at least one ink composition is 0.1% by weight or more and less than 1.5% by weight, and the concentration of the metal pigment in the other at least one ink composition is 1.5% by weight Above and below 3.0% by weight.

[recording device]

The recording device according to the present embodiment is a recording device including the ink set described above.

Next, the configuration of the recording head 3 of the inkjet recording device will be described. Here, FIG. 1 is a schematic perspective view of the recording head 3 housed in a carriage (not shown). In addition, FIG. 2 is a cross-sectional view of the ink introduction needle 19 inserted into the ink drum.

The illustrated recording head 3 has a drum base 15 (hereinafter referred to as "base"). A head housing 16 is attached to the base 15 . A flow path unit 17 is attached (arranged) to the tip of the head container 16 . The base 15 is molded, for example, from a synthetic resin, and a plurality of sections 15' (liquid storage member mounting portions) are provided thereon.

In each block 15', a mesh filter 18 is interposed, and an ink introduction needle 19 is attached. Next, ink drums (not shown) are installed in these sections 15'. That is, the ink drum is arranged on the base 15 . The details of the ink introduction needle 19 inserted into the ink drum will be described.

The circuit board 20 is mounted on the other surface of the base 15 which becomes the side opposite to the section 15'. Next, the circuit board 20 is attached to the base 15 via the sheet member 21 functioning as a spacer.

The head case 16 is a member fixed to the base 15 and is a case for accommodating a vibrator unit 22 having a piezoelectric vibrator. Next, the flow path unit 17 is fixed with an adhesive or the like to the front end surface of the head case 16 opposite to the mounting surface of the base 15 . The flow channel unit 17 is fabricated by laminating the elastic plate 23 , the flow channel forming substrate 24 , and the nozzle plate 25 sequentially and fixing them with an adhesive or the like to be integrated.

Here, the nozzle plate 25 is, for example, a plate-shaped member made of a thin stainless steel plate, and fine nozzle openings 26 are formed in a row at a pitch corresponding to the dot formation density of the printer. In addition, the head cover 27 is comprised, for example by a thin metal plate member.

As shown in FIG. 2, the ink liquid introduction needle 19 inserted into the ink drum is a hollow needle whose upper tip is formed into a conical shape and an ink liquid introduction path 41 is formed inside, and the lower half is formed to expand from upstream to downstream. cone shape. In addition, an ink introduction hole 42 that communicates with the external space and the ink introduction path 41 is opened on the tip side of the ink introduction needle 19 .

The ink introduction needle 19 is attached to the base 15 by, for example, ultrasonic welding with the mesh filter 18 interposed therebetween. As a result, the ink introduction passage 41 of the ink introduction needle 19 communicates with the ink communication passage 37 of the head case 16 .

Then, if the ink drum (not shown) is installed on the section 15' of the base 15, the ink introduction needle 19 is inserted into the needle insertion port of the ink drum, and the inner space of the ink drum and the ink introduction The ink introduction path 41 in the needle 19 communicates with the ink introduction needle 42 . Then, the ink stored in the ink drum is introduced into the ink introduction path 41 through the ink introduction hole 42 , passes through the ink communication path 37 , and is ejected from the nozzle opening 26 .

Here, when the diameter of the nozzle opening 26 of the recording head 3 of the inkjet recording device is L μm, and the mesh filter 18 provided in the ink introduction path 41 is W μm, the nozzle diameter L μm is related to the The mesh Wμm of the mesh filter preferably satisfies the condition of L≧5W. In the case of using an ink composition containing the pigment dispersion of this embodiment in an inkjet recording device satisfying such a relationship, it is possible to prevent clogging of the metallic pigment in the nozzle opening 26 and ensure stable discharge of the ink composition. From the standpoint of stability, when the equivalent circle diameter obtained from the area of the X-Y plane of the above-mentioned flat particles is R μm, the number of flat particles satisfying the condition of R>(L/5) is preferably flat particles. less than 5% of the total.

The ink composition of the present invention can eject its liquid droplets and attach the liquid droplets to a recording medium for recording.

From the viewpoint of angle dependence, it is preferable to form an image having a metallic luster as measured by specular gloss at 20 degrees, 60 degrees, and 85 degrees specified in JIS Z8741 on the recording medium. Simultaneously display 200, 200, and 100 or more, more preferably 20 degrees, 60 degrees, and 85 degrees of specular gloss measured by JIS Z8741, and simultaneously display 400, 400, and 100 or more, and more preferably use the value specified by JIS Z8741 The measured values of specular gloss at 20 degrees, 60 degrees, and 85 degrees were simultaneously displayed as 600, 600, and 100 or more, respectively.

Images that show a value of 200 to less than 400, 200 to less than 400, and 100 or more at the same time when the measured values of specular gloss at 20 degrees, 60 degrees, and 85 degrees specified in JIS Z8741 have a matte tone (matte tone) metallic luster.

Using the measured values of specular gloss of 20 degrees, 60 degrees, and 85 degrees stipulated in JIS Z8741, it is possible to distinguish how much the image has a value of 400 or more and less than 600, 400 or more and less than 600, and 100 or more at the same time. A lustrous metallic sheen to the degree of objects in the formed image.

Using the measured values of 20 degrees, 60 degrees, and 85 degrees of specular gloss specified in JIS Z8741, images with metallic luster that are simultaneously displayed as values of 600 or more, 600 or more, and 100 or more are clear, and the reflection can be clearly distinguished. The degree of luster of the object in the formed image is the so-called "specular luster" metallic luster.

Therefore, if the ink composition of the present invention is used to record, the measured values of the specular gloss of 20 degrees, 60 degrees, and 85 degrees stipulated by JIS Z8741 on the recording medium are simultaneously displayed as 200, 200, and 100, respectively. An image having a metallic luster with the above numerical values can form an image having a desired metallic luster ranging from a matte tone image to a gloss tone image.

On the other hand, when the measured values of specular glossiness at 20°, 60°, and 85° do not simultaneously show values of 200, 200, and 100 or more, the metallic luster cannot be felt when visually observing such an image. Observed as grey. In addition, when none of the measured values of the specular glossiness at 20 degrees, 60 degrees, and 85 degrees shows a numerical value greater than the above-mentioned numerical value, the effect of the present invention cannot be obtained.

From the viewpoints of securing the metallic gloss, the printing process, and the cost, the ejection amount of the ink composition ejected on the recording medium is preferably 0.1 to 100 mg/cm ² , more preferably 1.0 to 50 mg/cm 2 . cm ² .

The dry weight of the metallic pigment forming an image on the recording medium is preferably 0.0001 to 3.0 mg/cm ² from the viewpoint of metallic luster, printing process, and cost. The lower the dry weight of the metallic pigment is, the more highly glossy the metallic luster surface can be formed. Therefore, it is suitable for, for example, the case where a half-transparent mirror image is formed on a transparent recording medium. In addition, the higher the dry weight of the metallic pigment is, the more it is possible to form a metallic glossy surface with a matte tone. Therefore, it is suitable, for example, when forming a mask layer on a transparent recording medium.

Examples of the method for ejecting the ink composition include the methods described below.

The first method is the electrostatic attraction method. In this method, a strong electric field is applied between the nozzle and the acceleration electrode placed in front of the nozzle, ink is continuously ejected from the nozzle in the form of droplets, and the ink droplet flies to the deflection electrode. A method of giving a printing information signal to the deflection electrode from time to time for recording, or a method of ejecting ink droplets in response to the printing information signal without deflecting them.

The second mode is a mode in which ink droplets are forcibly ejected by applying pressure to the ink with a small pump and mechanically vibrating the nozzle with a crystal oscillator or the like. It is a system in which the jetted ink droplets are charged while ejecting, and when the ink droplets fly between the deflection electrodes, a printing information signal is given to the deflection electrodes for recording.

The third method is a method of using a piezoelectric element (piezo element), and a method of ejecting and recording ink droplets by simultaneously applying pressure and printing information signals to the ink using the piezoelectric element.

The fourth method is a method of rapidly expanding the volume of the ink by the action of thermal energy, and a method of ejecting and recording ink droplets by heating and bubbling the ink according to the printing information signal by using micro electrodes.

Any of the above methods can be used in the inkjet recording method of this embodiment, but from the viewpoint of supporting high-speed printing, the method of ejecting the ink composition is preferably a non-heating method. That is, it is preferable to employ the above-mentioned first method, second method, or third method.

The recording medium is not particularly limited, and for example, plain paper, ink-jet paper (matte paper, glossy paper), glass, plastic films such as vinyl chloride, films coated with plastic or a receiving layer on a substrate, metal, printing, etc., can be used. Various recording media such as printed circuit boards.

In the case where the recording medium has an ink receiving layer, it is preferable to print the recording medium non-heating from the viewpoint of not causing thermal damage.

On the other hand, when the recording medium does not have an ink-receiving layer, it is preferable to heat and print on the recording medium from the viewpoint of increasing the drying rate and obtaining high gloss.

Examples of heating include a method of bringing the recording medium into contact with a heat source, irradiating infrared rays or microwaves (electromagnetic waves having a maximum wavelength around 2,450 MHz), or a method of heating without contacting the recording medium, such as blowing hot air.

The heating is preferably performed before printing and/or simultaneously with printing and/or after printing. In other words, the heating of the recording medium can be performed before printing, at the same time, or after, or during the entire printing period. The heating temperature varies depending on the type of recording medium, but is preferably 30 to 80°C, more preferably 40 to 60°C.

According to the ink composition of the present invention, recording is performed by the above-mentioned inkjet recording method. Since the recorded matter is a recorded matter obtained by using a combined ink containing the above-mentioned ink composition, it can be obtained that the specular gloss at 20 degrees, 60 degrees, and 85 degrees respectively shows values of 200, 200, and 100 or more. Records with metallic specular luster. In addition, since the metal pigment concentration of the ink composition included in the ink set varies with each ink composition, any metallic luster from specular gloss to matte tone can be formed at the same time.

[Example]

[Example A]

1. Preparation of metal pigment dispersion

On a PET film with a film thickness of 100 μm, 3.0% by weight of cellulose acetate butyrate (35-39% butylation rate, manufactured by Kanto Chemical Co., Ltd.) and diethylene glycol diethyl ether (Nippon Emulsification Co., Ltd. Co., Ltd.) was dried at 60° C. for 10 minutes to form a resin layer film on a PET film.

Next, an aluminum vapor-deposition layer with an average film thickness of 20 nm was formed on the above-mentioned resin layer using a vacuum vapor deposition apparatus (Vacuum vapor deposition apparatus type VE-1010 manufactured by Vacuum Equipment Co., Ltd.).

Next, in diethylene glycol diethyl ether, using a VS-150 ultrasonic disperser (manufactured by Azuwan (Azuwan) Co., Ltd.), the laminate formed by the above method was simultaneously peeled, miniaturized, and dispersed, and the cumulative ultrasonic dispersion The treatment time was 12 hours, and a metal pigment dispersion liquid was prepared.

The obtained metallic pigment dispersion liquid was filtered through a SUS mesh filter with a mesh size of 5 μm to remove coarse particles. Next, the filtrate was put into a round bottom flask, and diethylene glycol diethyl ether was distilled off using a rotary evaporator. In this way, the metallic pigment dispersion liquid was concentrated, and then the concentration of the metallic pigment dispersion liquid was adjusted to obtain a metallic pigment dispersion liquid 1 with a concentration of 5% by weight.

In addition, metallic pigment dispersion liquids 2 to 11 having metallic pigments whose vapor deposition conditions and/or ultrasonic dispersion time were changed were obtained.

Next, using a particle size and particle size distribution measuring device (FPIA-3000S manufactured by Sysmex Corporation), the ratio of the equivalent circle diameter of the major axis (X direction) to the minor axis (Y direction) plane of each metal pigment was measured. 50% average particle size R50, average film thickness Z. Furthermore, R50/Z was calculated based on the obtained measured values of R50 and Z. Here, the particle size distribution value (CV value) is obtained by the calculation formula of CV value=standard deviation of particle size distribution/average value of particle diameter×100. The results are shown in Table 1.

[Table 1]

Metal Pigment Dispersion 50% average particle size R50(μm) Particle size distribution value (CV value) Average particle size Rmax(μm) Average film thickness Z(μm) R50/Z 1 1.03 44.0 4.9 0.02 51.5 2 1.43 48.9 6.9 0.02 71.5 3 2.54 47.2 7.2 0.02 127.0 4 1.13 44.8 5.9 0.02 56.5 5 1.02 48.4 5.7 0.03 34.0 6 0.91 45.1 4.2 0.02 45.5 7 0.86 46.6 4.3 0.02 43.0 8 0.89 38.2 3.2 0.02 44.5 9 5.52 81.2 30 0.10 55.2 10 1.42 65.0 12 0.30 4.7 11 1.40 60.2 7.1 0.30 4.7

2. Preparation of metallic pigment ink composition

Metallic pigment ink compositions were prepared with the compositions shown in Table 2 and Table 3 using the metallic pigment dispersion liquid prepared by the method described above. Mix and dissolve solvents and additives to form an ink solvent, then add metallic pigment dispersion liquid to the ink solvent, and then mix and stir with a magnetic stirrer at normal temperature and pressure for 30 minutes to obtain a metallic pigment ink composition .

In Table 2 and Table 3, diethylene glycol diethyl ether (DEGDE), dipropylene glycol monobutyl ether (DPGMB), and tetraglyme dimethyl ether (TEGDM) used products manufactured by Nippon Emulsifier Co., Ltd. In addition, the product manufactured by Kanto Chemical Co., Ltd. was used for γ-butyrolactone. Also, N-2043-60MEX and N-2043-AF-1 (resin emulsion) were manufactured by Harima Chemicals, and BYK-3500 (surfactant) was manufactured by BYK-Chemie Japan. Here, the unit is % by weight.

[Table 2]

Ink composition Example Comparative example 1 2 3 4 5 6 7 8 1 2 3 DEGDE 47.8 47.8 47.8 61.8 61.8 61.8 61.8 61.8 47.8 47.8 47.8 DPGMB 45 45 45 45 45 45 γ-butyrolactone 15 15 15 1 5 15 TEGDM 18 18 18 18 18 N-2043-AF-1 6.0 6.0 6.0 4.0 4.0 4.0 4.0 4.0 6.0 6.0 6.0 BYK-3500 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Pigment solids 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 (Metal Pigment Dispersion) (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11)

[table 3]

Ink composition Example 11 12 13 14 DEGDE 47.8 61.8 61.3 63.8 DPGMB 45.0 - - - γ-butyrolactone - 15.0 15.0 15.0 TEGDM - 18.0 18.0 18.0 N-2043-60MEX 6.0 4.0 4.0 2.0

BYK-UV3500 0.2 0.2 0.2 0.2 Pigment solids 1.0 1.0 1.5 1.0 (Metal Pigment Dispersion) (8) (8) (8) (8)

(3) Evaluation test

(1) Ejection stability

Using an inkjet printer EM-930C (manufactured by Seiko Epson Co., Ltd.), the black column was filled with the ink composition, and β printing was performed on photographic paper <glossy> (model: KA450PSK) made by the same company at room temperature.

At this time, the nozzle diameter (L) of the inkjet printer was 25 μm, and the mesh (W) of the mesh filter provided in the ink flow path was 5 μm. Therefore, the inkjet printer used has a relationship of L=5W. In addition, the average particle diameter (R) of the equivalent circle diameter obtained from the area of the X-Y plane of the tabular particles contained in the ink composition is calculated in the relationship with the nozzle diameter (L) of the above-mentioned inkjet printer. The ratio (%) of the number of tabular particles satisfying the condition of R>(L/5).

The obtained β image was visually observed for the presence or absence of discharge defects (nozzle omission), and the discharge stability was evaluated according to the following evaluation criteria. Here, "nozzle omission" means that the ink that should normally be ejected from the nozzles of the printer head is not ejected due to clogging of the nozzles, which affects the printing result. The evaluation results are shown in Table 3 together with the ratio (%) of the number of tabular particles satisfying the condition of R>(L/5).

AA: Even when 30 sheets of A4-size β images were printed continuously, no ejection defect (nozzle omission) occurred.

A: Even if 10 sheets of A4-sized β images were printed continuously, no ejection defect (nozzle omission) occurred.

B: When A4-size β images were printed continuously, ejection defects (nozzle omission) occurred from the second to less than 10 sheets.

C: When A4-size β images were printed continuously, ejection defects (nozzle omission) occurred on the first sheet.

(2) Determination of gloss

Using an inkjet printer EM-930C (manufactured by Seiko Epson Co., Ltd.), the ink composition is filled in the black row, and at room temperature, on the same company's photographic paper <glossy> (model: KA450PSK) having an ink receiving layer Perform beta printing. The discharge amount of the ink composition at this time was 1.2 mg/cm ² , and the dry weight of the metallic pigment was 12 μg/cm ² . The glossiness of the obtained image was measured using a gloss meter (MULTI Gloss 268 manufactured by Konica Minolta Co., Ltd.). The results are shown in Table 4 and Table 5.

[Table 4]

Record·Print Stability R＞L/5(%) Gloss 20° Gloss 60° Gloss 85° Gloss Example 1 A 1.2 283 363 107 Example 2 A 1.1 401 411 110 Example 3 A 4.4 225 372 103 Example 4 A ＜0.1 895 604 125 Example 5 A ＜0.1 733 553 121 Example 6 A ＜0.1 560 547 124 Example 7 A ＜0.1 626 483 120 Example 8 AAA ＜0.1 663 506 123 Comparative example 1 C 50 - - - Comparative example 2 B 3.1 171 311 104 Comparative example 3 B 4.3 333 409 116

-: Unaware

[table 5]

Record·Print Stability R＞L/5(%) Gloss 20° Gloss 60° Gloss 85° Gloss Example 11 AA ＜0.1 350 434 116 Example 12 AA ＜0.1 895 604 125 Example 13 AA ＜0.1 782 592 125 Example 14 AA ＜0.1 940 604 128

(3) Heating printing evaluation

Using an inkjet printer SJ-540 (manufactured by Lu Landi (Roland) DG Co., Ltd.), the ink composition of Example 1 is filled in the yellow column, and the glossy vinyl chloride (with gray paste) that does not have an ink receiving layer Paste) (model: SP-SG-1270G) for β printing and heat drying. Next, the glossiness of the obtained image was measured using a photometer (MULTI Gloss 268 manufactured by Konica Minolta Co., Ltd.). The results and heating conditions are shown in Table 6. However, the heating conditions were performed in the case of heating at 40° C. during printing (Example 9), and in the case of heating with a dryer at 60° C. after printing at normal temperature (Example 10). In addition, as a control, a case where only room temperature printing was performed without heating (reference example) was examined.

Similarly, the same case as in Example 9 (Example 15) was examined except that the ink composition of Example 13 was used.

[Table 6]

(3) Heating printing evaluation 20° Gloss 60° Gloss 85° Gloss Heating conditions Example 9 260 405 120 40°C during printing Example 10 218 406 117 60°C after printing Reference example 99 214 68 no heating

[Table 7]

(3) Heating printing evaluation 20° Gloss 60° Gloss 85° Gloss Heating conditions Example 15 275 408 116 40°C during printing

[Example B]

1. Preparation of metal pigment dispersion

In the same manner as in Example A, a metal pigment dispersion was prepared.

2. Preparation of metallic pigment ink composition

Using the metallic pigment dispersion prepared in Example A, metallic pigment ink compositions were prepared with the compositions shown in Tables 8 to 9. Mix and dissolve solvents and additives to form an ink solvent, then add metallic pigment dispersion liquid to the ink solvent, and then mix and stir with a magnetic stirrer at normal temperature and pressure for 30 minutes to obtain a metallic pigment ink composition .

In Tables 8 to 9, diethylene glycol diethyl ether (DEGDE) and tetraglyme dimethyl ether (TEGDM) were manufactured by Nippon Emulsifier Co., Ltd. In addition, the product manufactured by Kanto Chemical Co., Ltd. was used for γ-butyrolactone. Also, N-2043-60MEX and N-2043-AF-1 (resin emulsion) were manufactured by Harima Chemicals, and BYK-3500 (surfactant) was manufactured by BYK-Chemie Japan. Here, the unit is % by weight.

[Table 8]

Ink composition Example Comparative example 16 17 18 19 20 4 5 6 DEGDE 64.30 64.05 63.80 63.30 62.80 64.05 63.80 62.80 γ-butyrolactone 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 TEGDM 18.0 18.0 18.0 18.0 18.0 18.0 18.0 18.0 N-2043-AF-1 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 BYK-3500 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Pigment solids 0.50 0.75 1.00 1.50 2.00 0.75 1.00 2.00 (Metal Pigment Dispersion) (4) (4) (4) (4) (4) (10) (10) (10)

[Table 9]

Ink composition Example twenty one twenty two twenty three DEGDE 64.05 63.80 63.30 γ-butyrolactone 15.0 15.0 15.0 TEGDM 18.0 18.0 18.0 N-2043-60MEX 2.0 2.0 2.0 BYK-3500 0.2 0.2 0.2   Pigment solid content 0.75 1.00 1.50 (Metal Pigment Dispersion) (8) (8) (8)

3. Evaluation test

(1) Determination of gloss

Using an inkjet printer EM-930C (manufactured by Seiko Epson Co., Ltd.), the ink composition is filled in the black row, and at room temperature, on the same company's photographic paper <glossy> (model: KA450PSK) having an ink receiving layer Perform beta printing. The discharge amount of the ink composition at this time was 1.2 mg/cm ² , and the dry weight of the metallic pigment was 12 μg/cm ² . The glossiness of the obtained image was measured using a gloss meter (MULTI Gloss 268 manufactured by Konica Minolta Co., Ltd.). Furthermore, functional evaluation of the printed matter was performed based on the following evaluation criteria. The results are shown in Tables 10 and 11.

AA: Specular gloss (reflected objects can be distinguished well. There is clarity)

A: Gloss (metallic luster can be felt, but no clarity)

B: Matte tone (matte metallic luster)

C: gray tone (metallic luster cannot be felt, observed as gray)

[Table 10]

Gloss Functional evaluation of printed matter 20° Gloss 60° Gloss 85° Gloss Example 16 331 345 118 B Example 17 698 510 123 AA Example 18 895 604 125 AA Example 19 782 592 125 AA Example 20 531 512 120 A Comparative example 4 158 286 102 C Comparative Example 5 171 311 104 C Comparative Example 6 117 301 106 C

[Table 11]

Gloss Functional evaluation of printed matter 20° Gloss 60° Gloss 85° Gloss Example 21 910 571 124 AA Example 22 940 604 128 AA Example 23 826 595 126 AA

From the above results, it can be judged that the ink compositions (Examples 16 to 20) used in the ink set of the present invention can form images having different metallic luster depending on the concentration of the metallic pigment. Therefore, it can be seen that the combined ink with the ink composition having different concentrations of the metallic pigment has a high metallic specular gloss with a specular gloss of 20 degrees, 60 degrees, and 85 degrees respectively showing values of 200, 200, and 100 or more, and can simultaneously Prints prints from specular gloss to matte shades.

Claims (15)

1. dispersible pigment dispersion, this dispersible pigment dispersion contains metallic pigment, wherein,

Described metallic pigment are the tabular particle, at this tabular particle major diameter in the plane is that X, minor axis are that Y, thickness are under the situation of Z, 50% median size R50 of the diameter of equivalent circle of trying to achieve from the area of the X-Y plane of this tabular particle is 0.5～3 μ m, and satisfies the condition of R50/Z＞5.

2. dispersible pigment dispersion according to claim 1, wherein,

The maximum particle diameter Rmax of the diameter of equivalent circle of trying to achieve from the area of the X-Y plane of described tabular particle is below the 10 μ m.

3. dispersible pigment dispersion according to claim 1, wherein,

Described metallic pigment are aluminum or aluminum alloy.

4. dispersible pigment dispersion according to claim 1, wherein,

Described metallic pigment make by broken metal evaporation film.

5. dispersible pigment dispersion according to claim 1, wherein,

The size-grade distribution CV value of the described metallic pigment of trying to achieve with following formula is below 60.

[formula 1]

The mean value of the standard deviation/particle diameter of CV value=size-grade distribution * 100

6. ink composition, wherein,

Described ink composition contains the described dispersible pigment dispersion of claim 1, organic solvent and resin.

7. ink composition according to claim 6, wherein,

The concentration of described metallic pigment in ink composition is 0.1～3.0 weight %.

8. ink composition according to claim 6, wherein,

Described organic solvent contains more than one and is the alkylene glycol ether of liquid at normal temperatures and pressures.

9. ink composition according to claim 6, wherein,

Described organic solvent is the mixture of alkylidene diol bisether, aklylene glycol one ether and lactone.

10. ink composition according to claim 6, wherein,

Described resin is more than select from the group that polyvinyl butyral acetal, cellulose acetate butyrate, polyacrylic acid polyvalent alcohol constitute at least a.

11. ink composition according to claim 6, wherein,

Described ink composition contains more than one acetylenediol system and/or silicone-based tensio-active agent at least.

12. ink composition according to claim 6, wherein,

When the nozzle diameter L μ m that is applied to ink gun and the mesh W μ m that is arranged at the web filter in the black liquid runner satisfied the ink-jet recording device of condition of L 〉=5W, the tabular population that the median size R μ m of the diameter of equivalent circle of trying to achieve from the area of the X-Y plane of described tabular particle satisfies the condition of R＞(L/5) was below 5% of integral body of described tabular population.

13. an ink set, wherein,

Possesses the described ink composition of multiple claim 6, the metallic pigment concentration difference of described each ink composition.

14. ink set according to claim 13, wherein,

In described ink composition, the concentration of the metallic pigment of at least a ink composition is that 0.1 weight % is above and less than 1.5 weight %, the concentration of the metallic pigment of other at least a ink compositions is more than the 1.5 weight % and below the 3.0 weight %.

15. a recording unit, wherein,

Possesses the described ink set of claim 13.

Images